by Jeff Gluck, USA TODAY Sports

by Jeff Gluck, USA TODAY Sports

Jason Leffler's fatal June 12 accident was the result of a mechanical failure, the New Jersey State Police said Friday.

An investigation into Leffler's crash at Bridgesport (N.J.) Speedway found the front suspension failed on Leffler's 410 sprint car during the fifth lap of a heat race while he was in second place.

Leffler's steering locked up and he lost control of the car, according to Lt. Stephen Jones. The car turned around and hit the outside concrete rail with the left side of his car, then flipped and slid until it came to a rest on its wheels.

The coroner ruled earlier Leffler was killed as a result of blunt force injury to the neck.

According to his team, Leffler was wearing a Simpson Hybrid head and neck restraint system, which is one of six approved for use in NASCAR. A blunt force injury occurs when an object strikes the body with force causing compression of tissue. Head and neck restraints are designed to prevent injuries resulting from deceleration trauma when the body is moving and strikes another moving or stationary object, causing stretching or tearing of body tissue.

Jones said the front suspension failed due to a torsion bar sliding out of the car. When it did, the torsion arm became lodged between the right front wheel and the right front steering arm â?? which is what caused Leffler's steering to lock up.

Drivers averaged 135 mph during the event and reached speeds of about 150 mph on the straightaways, Jones said. It is not known how fast Leffler's car was going when the part failed.

Sprint Cup driver Dave Blaney witnessed the crash at the dirt track, where he was scheduled to race in two events later in a program that was canceled after Leffler's death.

"Talking with the guys in that race and the place on the racetrack where he wrecked, the odds are really good something broke on the race car and got him into the fence," Blaney said June 14 at Michigan International Speedway. "Even in those cars, you just don't see that kind of thing very often. You don't forget it's part of it, but anymore, it's rare. But it's still there."

Leffler's resilient personality and versatile grit made him popular and respected among peers while racing in all three of NASCAR's national series. He was remembered at his funeral Wednesday as a doting father and true racer.